The present invention relates to a suspension stop device, intended in particular for suspension systems of the McPherson type for the steered wheels of a motor vehicle.
The suspension devices of motor vehicles generally contain a suspension-stop rolling bearing whose function is to transmit the axial and radial forces resulting from compression of the spring and at the same time to permit practically frictionless rotation between the spring and the vehicle body, this rotational movement of the spring taking place while the steered wheels are being turned and during variations of compression of the spring by a winding-up effect of the coils.
A current solution, whose view in axial section is illustrated in FIG. 1, generally contains two components, a suppression block 1, intended to suppress the movements of the shock-absorber rod 2 and of the spring 6 relative to the body 3 of the vehicle along the axis xcex94 of the rod, and a ball bearing 4, maintained in a housing 5, intended to transmit the displacements of spring 6 in a plane P.
Suppression block 1 is made of rubber 10 or elastomer, bonded to a sheet-metal frame 11. It is integral with body 3, with which it is in contact by a bolt or other means.
Ball bearing 4 is seated between two bearing rings 5 forming a housing, of steel, for example, upper ring 51 being fixed and integral with the vehicle, while lower ring 52 is rotationally movable. This lower ring 52 also functions as support for suspension spring 6 of the device.
Shock-absorber rod 2 is fixed to the suppression block by a nut 7.
This current structure of a suspension stop device has a fairly large number of parts of different nature, which must be manufactured then assembled, resulting in a relatively complex and expensive device.
The present invention proposes to replace the current structure of the metal suppression block to which the rubber is bonded by a thermoplastic structure that, in addition to suppressing vibrations and noise, performs the function of a ball-bearing housing and the function of a bump stop, thus reducing the number of parts of the suspension stop device and therefore its cost price.
For that purpose the object of the invention is a suspension stop device for the driving wheels of a motor vehicle, comprising on the one hand a suppression block composed of an upper case fixed relative to the vehicle body and cooperating with a lower case that can move rotationally around a shock-absorber rod and serving as support for a suspension spring, and on the other hand a ball bearing, characterized in that the said upper and lower cases are made of thermoplastic material and have opposite faces containing a circular hollow around the axis of rotation of the shock-absorber rod in order to receive a raceway in the ball bearing, the upper case also integrating a bump stop molded around the striking stop of the shock-absorbing device, and in that the thermoplastic structure of the upper case is reinforced by a crown of overmolded elastomer.
According to another characteristic, the two upper and lower cases of the suppression block are made of fiberglass-reinforced thermoplastic material.